US20110038012A1 - Method and device against forgery - Google Patents

Method and device against forgery Download PDF

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Publication number
US20110038012A1
US20110038012A1 US12/519,256 US51925607A US2011038012A1 US 20110038012 A1 US20110038012 A1 US 20110038012A1 US 51925607 A US51925607 A US 51925607A US 2011038012 A1 US2011038012 A1 US 2011038012A1
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United States
Prior art keywords
image
determining
print
dac
digital authentication
Prior art date
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Abandoned
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US12/519,256
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English (en)
Inventor
Jean-Pierre Massicot
Alain Foucou
Zbigniew Sagan
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Advanced Track and Trace SA
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Advanced Track and Trace SA
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Filing date
Publication date
Priority claimed from FR0610891A external-priority patent/FR2910148B1/fr
Priority claimed from FR0611402A external-priority patent/FR2910667B1/fr
Priority claimed from FR0703922A external-priority patent/FR2916678B1/fr
Priority claimed from FR0704517A external-priority patent/FR2917877B1/fr
Application filed by Advanced Track and Trace SA filed Critical Advanced Track and Trace SA
Assigned to ADVANCED TRACK AND TRACE reassignment ADVANCED TRACK AND TRACE ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: FOUCOU, ALAIN, MASSICOT, JEAN-PIERRE, SAGAN, ZBIGNIEW
Publication of US20110038012A1 publication Critical patent/US20110038012A1/en
Abandoned legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B42—BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
    • B42D—BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
    • B42D25/00—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
    • B42D25/40—Manufacture
    • B42D25/405—Marking
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/32—Circuits or arrangements for control or supervision between transmitter and receiver or between image input and image output device, e.g. between a still-image camera and its memory or between a still-image camera and a printer device
    • H04N1/32101—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title
    • H04N1/32128—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title attached to the image data, e.g. file header, transmitted message header, information on the same page or in the same computer file as the image
    • H04N1/32133—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title attached to the image data, e.g. file header, transmitted message header, information on the same page or in the same computer file as the image on the same paper sheet, e.g. a facsimile page header
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/32—Circuits or arrangements for control or supervision between transmitter and receiver or between image input and image output device, e.g. between a still-image camera and its memory or between a still-image camera and a printer device
    • H04N1/32101—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title
    • H04N1/32144—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N2201/00—Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
    • H04N2201/32—Circuits or arrangements for control or supervision between transmitter and receiver or between image input and image output device, e.g. between a still-image camera and its memory or between a still-image camera and a printer device
    • H04N2201/3201—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title
    • H04N2201/3225—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title of data relating to an image, a page or a document
    • H04N2201/3233—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title of data relating to an image, a page or a document of authentication information, e.g. digital signature, watermark

Definitions

  • This invention concerns a method and a device for fighting against counterfeiting. It concerns, in particular, the production and exploitation of digital authentication codes (“DAC”).
  • digital authentication codes these digital authentication codes, this invention applies in particular to copy detection patterns (“CDP”), secured information matrices (“SIM”), arranged dot patterns and/or digital watermarks, to the secured and robust production, tracking and authentication of manufactured items and products, packaging, etc.
  • the holders of these intellectual property rights wish above all to measure the extent of the problem or problems they are confronted with: are they faced with counterfeiting or grey market problems, or a combination of both, in which markets, etc?
  • the owners of intellectual property rights in particular trademarks, models and designs, and the organizations that generate official documents and that have adopted encrypted two-dimensional (“2D”) bar codes or other data carriers, such as RFID (acronym for “Radio Frequency Identification”) electronic tags, to help them solve their forgery problems, must nevertheless use radically different authentication methods (“authenticators”), such as holograms, security inks, microtexts, or so-called “guilloche” patterns (fine curved lines interfering with digital reproduction systems, for example through a watermark effect), to avoid or detect slavish counterfeiting.
  • authentication methods such as holograms, security inks, microtexts, or so-called “guilloche” patterns (fine curved lines interfering with digital reproduction systems, for example through a watermark effect), to avoid or detect slavish
  • DACs offer an interesting alternative to traditional methods of securing documents.
  • “all-digital” age they offer an essentially digital solution that has all the functionalities required, i.e. traceability of products, automatic authentication (detection of copies), detection of forgeries. They dematerialize the procedure for producing secure documents: a trademark is inserted by modifying a digital file of a document, or by adding an image that is an authenticator (i.e. that allows copies to be detected automatically) and, possibly, an identifier, to it. Reading is done by automatically processing a digital image capture of a document; the reader may possibly be connected to a secured database.
  • DACs are especially interesting for the holders of rights on manufactured products that have particularly stringent cost and production requirements: in effect DAC image files can be ordered, sent and received instantaneously.
  • DACs Another advantage of the DACs is the possibility of using standard image capture devices, such as mass-market scanners or digital cameras, possibly integrated in digital personal assistants (or mobile telephones), to verify the DACs.
  • image capture devices such as mass-market scanners or digital cameras, possibly integrated in digital personal assistants (or mobile telephones)
  • DACs digital personal assistants
  • These make the large-scale deployment of DACs possible, given the low cost and ease with which such capture devices can be obtained.
  • a security ink requires a dedicated reader, often costly, and obliges the rights holder to commit to a solution that is vulnerable and costly to implement, with the consequences and risks this entails.
  • DACs are specific digital authentication codes.
  • Other DACs include digital watermarks and arranged dot patterns, if these have authentication properties.
  • Digital authentication codes, DACs present the potential, at least in theory, of tracking each document or product individually.
  • SIMs are representations of matrix information on a surface, which can be read by a machine from an image capture. But unlike 2D bar codes (which are in two dimensions), SIMs are not simply “containers” of information: they are designed so as to ensure the security of the documents on which they are printed. In particular they enable many problems to be dealt with concerning the counterfeiting (identical copies, reproductions) or forging (expiry date for a medicine, identity card, etc) of documents, and ensure their traceability, notably making the fight against the grey market possible. Of course, some of these problems can be partially dealt with by ordinary 2D bar codes, such as Datamatrix (registered trademark), through the addition of a cryptographic layer protecting the writing and reading of messages.
  • Datamatrix registered trademark
  • SIMs offer much more extensive handling of the problems relating to security.
  • SIMs make it possible to detect cases of counterfeiting via true copy or photocopy, which in theory is not possible with the other types of information matrices.
  • any copy of an original printed SIM can be detected.
  • the error rate for decoding the message carried by the copied SIM is greater than the maximum tolerated error rate for an original printed SIM.
  • SIMs offer the possibility of using different read or write permission levels, each locked by a cryptographic key, each permission level corresponding to a security layer: if a cryptographic key is compromised only the corresponding security layer is affected.
  • SIMs enable all the values related to the document's traceability to be stored in a secure way, such as, for example, a unique identity number, an expiry date, a manufacturing order, a provenance, a destination market, etc. It is advantageous for each SIM to be unique, i.e. one SIM carrying a specific message can only be printed once: we then talk of “serialized” printing. In this way, it is ensured that each of the existing documents can be uniquely identified. SIMs are generally used in this way for digital types of printing methods, i.e. in which a processor communicates directly with the print means and can vary the contents printed, in particular with digital, laser, ink-jet print means allowing the serialized printing of SIMs.
  • Copy detection patterns, CDPs are a type of visible authentication patterns, which generally appear to be noise and are generated from a key in a pseudo-random way. These copy detection patterns, CDPs, are basically used to distinguish original printed documents and printed documents copied from the former, for example by photocopying or using a scanner and a printer. This technique operates by comparing a captured image of an analog, i.e. real-world, copy detection pattern with an original digital representation of this pattern to measure the degree of difference between the two of them. The underlying principle is that the degree of difference is higher for the captured image of a pattern that has not been produced from an original analog pattern, as a result of degradation during copying. To carry information, the CDP's image is divided into areas and each area can contain different configurations of pixel values (all appearing to be noise), each configuration being associated to a binary value.
  • the operating principle during reading can often be equated to the energy level measurement of a signal in the captured image, subsequently known as the “score”, which is compared against a threshold value, generally pre-defined: if the score is greater than this threshold value, it is deduced that the image is an original. If not, it is deduced that it is a copy. There can also be a “grey” area of indecision in the area around the threshold value, where the decision is not clear-cut, and if the score is located in this area a new image capture is requested.
  • the score can be, for example, measured as a decreasing function of the captured SIM's error rate.
  • the CDPs it can be measured as the index of similarity between the original CDP and the captured CDP.
  • the score can be measured by the degree of correlation between the original watermark, i.e. the signal before its modulation in the marked image, and the captured image, once the image has been filtered in the suitable frequency spectrum and the signals have been synchronized.
  • the score can be measured by the value at the peak of cross-correlation between the original dot pattern and the dot pattern in the captured image. It is noted that numerous other measurements are possible, and in particular that the distance measurements can be inverted to represent measurements of closeness or similarity.
  • the value of the threshold (or possibly the thresholds if the “grey” area of indecision described above is used) is generally pre-calculated by making use of the statistical distribution of the scores for a sample representative of all the original DAC prints. Techniques known in prior art are used for estimating the average, variance or standard deviation, and the theoretical probabilities (one could, for example, consider that an original is much more probable than a copy) are sometimes used. Cost factors can be assigned to the detection system's error types, in which case a threshold value that minimizes this risk is defined. For example, in some applications it is considered more acceptable for an original to be wrongly detected as a copy than the opposite, since, for a “copy” decision, a second reading that will confirm or dispel the doubts can be performed.
  • the DACs can be invisible or at least difficult to see, for example a digital watermark vulnerable to copying integrated in the image, or a pseudo-randomly arranged dot pattern, also known as an “AMSM”.
  • the pseudo-randomly distributed dots present a certain density, low enough to be difficult to locate, for example with a density of 1%.
  • a score relating to the peak of cross-correlation between the reference AMSM and the captured AMSM corresponds to the signal's energy level, and theoretically it will be lower for the copies.
  • FIGS. 4 and 5 show two distributions 905 and 915 of scores for the original prints and two hypothetical distributions 910 and 920 for the copies (in effect, as has been said, properly speaking there is no universal distribution of the copies' scores), when the production of original documents is properly controlled, as shown in FIG. 4 , and when it is poorly controlled, as shown in FIG. 5 .
  • the distribution 905 of the originals' scores follows a Gaussian distribution, and the separation from the copies' scores 910 is clear: all the original prints have been carried out in identical conditions.
  • the distribution of the originals' scores 915 is more widespread and the ability to completely separate the originals' scores 915 and copies' scores 920 is no longer certain, the area (a) shown by an arrow corresponding to values of scores where relying on the result from the detector cannot be made.
  • the spread of the distribution of the originals' scores corresponds to a combination of the distributions illustrated in FIGS. 4 and 5 with respective proportions of 3 ⁇ 4 and 1 ⁇ 4: these distributions correspond to production conditions that may be in part different.
  • the image capture tool's internal parameters can also have an impact.
  • the image quality, and therefore the score, of a DAC captured with a scanner can vary according to the image capture resolution, number of bits per pixel, etc.
  • an image capture device can realize poor image captures. For example, if an object containing a DAC is poorly positioned on a scanner, the captured image may be blurred. If a portable tool is used and if the operator does not take care, the image can have a sharpness problem due to a movement or positioning the DAC outside the focal plane. Typically, the DAC's score can be noticeably lower and an original can therefore be detected as a copy.
  • FIG. 6 shows, in the upper portion, a statistical distribution of scores for the originals, 925 , and the copies, 930 , calculated based on images taken with a reference image capture tool, a calculated threshold value minimizing the average error rate for this distribution.
  • this figure shows the statistical distribution of scores for the same originals, 935 , and copies, 940 , based on images captured by another, lower quality, image capture tool.
  • the threshold value as calculated for the reference image capture tool, is indicated on it, at 945 . It can clearly be seen that the threshold value used is not adequate and may lead to numerous detection errors.
  • the score represented in FIG. 6 is divided by five with respect to the score represented in FIGS. 4 and 5 .
  • the limit value which has a value of 12 in FIG. 6 , corresponds to a score of 60 in FIGS. 4 and 5 .
  • the DAC verification tools can operate either locally or linked to a server.
  • the danger is that a counterfeiter gets hold of a module and carries out “reverse engineering” in order to determine the read algorithms used, to deduce the corresponding generation algorithms from these (the read algorithms are generally symmetrical with the DAC generation algorithms) and above all get hold of cryptographic keys stored in the module.
  • This invention thus aims, according to its various aspects, to remedy the difficulties of integrating and/or using DACs, in particular the problems of security, stability and lack of flexibility in integrating DACs for the production of secure documents and/or the problems of security, stability and lack of flexibility in using DACs for the verification of secure documents.
  • the present invention envisages a method for reading a digital authentication code, characterized in that it comprises:
  • the step of determining capture conditions for said image comprises a step of determining a value representative of the quality of said image's capture.
  • the step of determining an image's capture conditions comprises a step of determining a value representative of the blurring of said image's capture.
  • the step of determining the authenticity first of all it is determined whether the value representative of the blurring represents blurring below a pre-defined value and, if it is, whether the error rate is below a pre-defined value.
  • the method returns to the steps of capturing an image, of determining the error rate and of determining authenticity are repeated.
  • the value representative of the blurring represents blurring below a pre-defined value
  • at least one part of said image is transmitted to a remote server and the step of determining authenticity is carried out by said remote server.
  • More complex processing can therefore be carried out by a system having more resources in terms of processing capacity.
  • the step of determining first of all it is determined whether the error rate is below a pre-defined value and, if not, whether value representative of the blurring represents blurring below a pre-defined value.
  • the step of determining a value representative of the blurring utilizes values representative of the digital authentication code's print conditions.
  • the method that is the subject of the present invention comprises, after the step of capturing an image and before the step of determining authenticity, a step of detecting the presence of a digital authentication code in said image, the steps of determination only being carried out if there is a digital authentication code in said image and the step of capturing an image being repeated if the digital authentication code is absent from said image.
  • the procedure can be applied to a series of captured images, without the user needing to initiate the capture of an image.
  • a square or rectangular shape is automatically searched for.
  • a value is determined that is representative of a gradient in a digital authentication code.
  • the blurring represented by this gradient is easily determined, especially when the blurring comes from a faulty positioning of the digital authentication code with respect to the sharpness plane conjugated with the capture plane by the lens of the image capture means.
  • a Sobel filter is utilized.
  • a Gaussian filter is utilized.
  • the method that is the subject of the present invention comprises:
  • an image of a card is captured, the method that is the subject of the present invention, as described in brief above, comprising a step of reading, on said card, an identifier of the card carrier and a step of verifying said carrier's authorization to carry out a step of determining authenticity.
  • the step of determining an image's capture conditions comprises a step of determining the number of dots of said image that correspond to a digital authentication code.
  • the step of determining the number of dots of said image that correspond to a digital authentication code comprises a step of determining the resolution of the image capture device as the number of dots per unit of surface area placed in its sharpness plane.
  • the print sharpness of the digital authentication code is determined.
  • said sharpness is determined by reading, in the digital authentication code's content, a type of printing used to print said digital authentication code.
  • the method that is the subject of the present invention comprises:
  • the present invention envisages a device for reading a digital authentication code, characterized in that it comprises:
  • the unresolved problems include in particular the security of digital files and the stability of the marking.
  • the security of digital files when a DAC is printed or marked on a product it is, in theory, almost impossible to copy with a sufficiently high quality so as to confuse the copy and the original.
  • a DAC is generally presented in the form of an image file, which allows an unlimited number of authentic DACs to be produced. It therefore appears essential to protect this file throughout its life.
  • a digital image file can pass through several hands, be integrated in a product design or prepress file, etc. Often rights holders are obliged to entrust this file to the processor, for example a printer, over whom they have little control.
  • the image file is not printed directly but passes through at least one analog transformation step, for example when the plate is created and sometimes when the film is created that is used to make the plate, etc.
  • analog transformation step for example when the plate is created and sometimes when the film is created that is used to make the plate, etc.
  • These plates or films must also be protected since they allow authentic DACs to be generated.
  • there is no means of control ensuring that the processor, authorized by the rights holder to produce a given number of documents, has not produced a surplus quantity that they will sell to an unauthorized third party.
  • DACs require an especially stable print process in order to work properly.
  • the operating principle can often be equated to the energy level measurement of a signal in the captured image, subsequently known as the “score”, this score generally being higher for the original documents than the copies (distance measurements in which, as a general rule, the distance will be less for the original documents than for the copies can also be used). It is essential for this score to be as “stable” as possible for the original prints. In effect, the greater the statistical distribution of the scores of the original prints, the less this score makes it possible to differentiate effectively between the originals and the copies.
  • the means of marking comprise numerous adjustment parameters that are dependent, for example, on the product to be marked, the substrate or the inking, and which can significantly affect the DAC's score.
  • these parameters can also change over time, be adjusted differently by different operators, etc. Without complete control over the means of producing documents, the ability to detect copies can be significantly reduced.
  • the integration errors risk being so numerous that they can make the system unusable, or significantly reduce its credibility.
  • an integration error take the case of a sub-contractor, having to handle the insertion of several DACs into several products, who inserts a DAC into a document that does not correspond to it.
  • the present invention envisages a method for checking the print quality, characterized in that it comprises:
  • the print quality is checked by processing an image of the digital authentication code and the printing of carrier(s) only continues if the image quality is sufficiently high.
  • the print quality is determined according to an information content of the digital authentication code read in said image.
  • the information content identifies a carrier type (for example paper or cardboard, colors, glazing, etc).
  • an error rate is determined in the digital authentication code read in said image, the image quality being a function of said error rate.
  • the quality measurement can be standardized. It is noted that, during subsequent processing of the carrier, the digital authentication code can be separated from the useful part, this digital authentication code thus being used solely to determine the carrier's print quality.
  • the method that is the subject of the present invention comprises a step of determining if said image both allows a value borne by the printed digital authentication code to be read and presents an error rate less than a pre-defined limit value.
  • the method that is the subject of the present invention comprises a step of determining said pre-defined limit value according to the value represented by the digital authentication code.
  • the method that is the subject of the present invention comprises:
  • the initial print quality can be taken into account when subsequently determining whether a carrier is an original or a copy, which makes the method that is the subject of the present invention more reliable and easier to make operational.
  • said step of determining the image quality comprises the determination of an error rate for each one of a plurality of said images and, during the step of storing, an error rate limit value is stored, according to said determined error rates.
  • the operator is asked for a minimum of readings, for example 30, taken in a uniform way during the production, so as to determine the error rate statistics, or “score” for the production.
  • the method that is the subject of the present invention comprises, performed by a server that supplies digital authentication codes:
  • the server transmits, first of all, at least one control file allowing a digital authentication code to be printed that cannot be used, because of its information content, for authenticating a carrier production and, if the production is valid, the server transmits at least one other digital authentication code representative of information linked to said production.
  • the method that is the subject of the present invention comprises:
  • the method that is the subject of the present invention, as described in brief above, comprises a step of determining a signature of each captured image of a digital authentication code, and a step of storing said signature in a database, with the information relating to the production run.
  • the method that is the subject of the present invention comprises a step of printing an information matrix representing said signature on the document bearing the DAC corresponding to said signature.
  • the method that is the subject of the present invention comprises:
  • said analysis parameter values are representative of a print error rate of the digital authentication codes and by which, during the step of determining a rating, said rating is representative of a difference between the error rate represented by the analysis parameter values and the error rate determined from said image.
  • the method that is the subject of the present invention, as described in brief above, comprises a step of determining an average error rate from at least one digital authentication code image and, from a pre-defined instance, during the step of determining a rating, said rating is representative of a difference between said average error rate and the error rate determined from at least one new digital authentication code.
  • the method that is the subject of the present invention comprises a step of transmitting an alarm when said difference is greater than a pre-defined limit value.
  • the method that is the subject of the present invention comprises a step of associating a microtext to the digital authentication code, said microtext being printed with the digital authentication code that is associated to it.
  • the present invention envisages a device for checking the print quality, characterized in that it comprises:
  • This invention also concerns a method and a device for securing documents. It applies, in particular, to the printing of marks allowing an original to be distinguished from a copy.
  • a copy detection mark is produced in such a way that any copy, whether by photocopying or by taking an image and then printing the captured image, gives rise to a degradation of its details and allows this degradation to be detected, with a suitable reading and processing system.
  • the reading system measures the degradation and compares it, generally, to a pre-defined limit, or threshold, value.
  • the present invention envisages a method for making a so-called “original” document secure, which comprises:
  • the mark is optimized according to the characteristics of the item of print equipment and the limit value used by the detection equipment takes into account this print equipment's actual print quality.
  • the method comprises a step of printing at least one print reference representative of an authorized maximum or minimum inking for printing said document and, during the step of determining the first limit value, a measurement is determined over at least one said print reference and a tolerance is added to it.
  • the method comprises a step of measuring the deterioration of the mark on the print chain, a step of comparing this measurement with a second pre-defined limit value and, if the second deterioration limit value is exceeded, a step of warning.
  • the second limit value can be identical to the first limit value. Thanks to these provisions, the printer can be automatically notified when the print quality degrades and rectify the print equipment's settings.
  • the present invention envisages a computer program that can be loaded in a computer system, said program containing instructions allowing the method that is the subject of the present invention, as described in brief above, to be utilized.
  • the present invention envisages a data carrier that can be read by a computer or microprocessor, removable or not, holding the instructions of a computer program, characterized in that it allows the method that is the subject of the present invention, as described in brief above, to be utilized.
  • FIG. 1 represents, schematically, a particular embodiment of the device producing digital authentication codes that is the subject of this invention
  • FIGS. 2A and 2B represent, in the form of a logical diagram, steps utilized in a particular embodiment of the method producing digital authentication codes that is the subject of this invention
  • FIGS. 3A to 3H represent, in the form of a logical diagram, steps utilized in a particular embodiment of the method reading digital authentication codes that is the subject of this invention
  • FIGS. 4 and 5 represent distributions of digital authentication code scores
  • FIG. 6 represents statistical distributions of scores for originals and copies calculated based on images taken with a reference image capture tool and with an image capture tool of a lower quality
  • FIGS. 7A and 7B represent, in the form of logical diagrams, steps utilized in a particular embodiment of the method that is the subject of this invention.
  • FIG. 8 represents, schematically, a particular embodiment of a device able to utilize the method that is the subject of this invention
  • FIGS. 9A and 9B represent, in the form of a logical diagram, steps utilized in a particular embodiment of the method that is the subject of this invention.
  • this invention is applied to digital authentication codes taking the form of square areas comprising square cells printed in black on a white background, the white areas presenting, in the initial digital image, the same surface area, in numbers of dots, or pixels, as the black areas.
  • this invention is not restricted to this type of application but, quite the contrary, extends to any type of DAC digital image allowing original prints to be (automatically) distinguished from copies based on the measurement of a score of the digital image printed and then digitized, said score varying according to the quantity of degradation the image has undergone.
  • all the DACs have the same problems of reliability and security with regard to controlling the score and checking the source image and:
  • Each step of creating the digital authentication code is carried out with the aim of the original message being readable without error, even if, and this is a wished-for effect, the initial reading of the digital authentication code is marred by errors.
  • one of the aims of this digital authentication code creation is to use the number or rate of errors of modulated message in order to determine a score, and then the authenticity of a print of this digital authentication code. In effect, a copy of the initial print of the DAC will generally bear more errors than this initial print of the DAC.
  • the image of the digital authentication code is created from one (or possibly several) message and one (or possibly several) key: typically, the source message is transformed into a binary representation and then encrypted by the key; the encrypted message is encoded so as to be robust to a high number of errors, then the encoded message is scrambled by the key before being modulated in the form of an image, each binary value being represented by a pixel of the image forming the digital authentication code.
  • the image forming the digital authentication code is printed at a resolution ensuring, from this initial print, an error rate that is significant (i.e. a low score) without being too high, such that the decoding of the encoded message containing the errors is guaranteed, as well as the detection of a possible copy of the digital authentication code, which necessarily comprises more errors.
  • the error rate or the score
  • the error rate can be adjusted according to print characteristics, such that the production of a copy gives rise to additional errors, resulting in an error rate that is, on average, higher, or a score that is lower, when a copy is read than when an original is read.
  • an error rate of 20% during the original printing is adequate, even though rates from 5% to more than 30% can work. It is noted that, for an error rate that is too low, a copy that is perfect and therefore indistinguishable from originals may be feasible, while for an error rate that is too high, the digital authentication code may not be decoded correctly and there may no longer be enough information that can be degraded during copying.
  • the coded message extracted from a captured copied digital authentication code therefore has more errors than the coded message extracted from a captured original digital authentication code.
  • the number or rate of errors detected is used to distinguish a copy from an original, by means of the score, which is a decreasing function of this error rate.
  • a major challenge consists of determining an appropriate decision threshold allowing the best possible distinction between originals and copies.
  • the rights holder orders a specified number of documents or products made secure by a DAC or DACs from an authorized processor or printer. This latter downloads one or more DACs, respectively for printing the same DAC on all the documents or for printing different DACs on different documents.
  • the processor prints the specified number of documents, with the specified DAC or DACs on each documents utilizing at least one aspect of this invention.
  • the specified number of printed documents is sent to the rights holder.
  • the documents are sent to the assembler authorized by the rights holder.
  • the rights holder or the assembler assembles the finished product (which can contain several “documents” made secure by DACs) and utilizes at least one aspect of this invention.
  • the rights holder authorizes the DAC provider to supply at least one DAC to the printer.
  • the DAC provider supplies a test DAC and a pre-defined threshold value that can be dependent on the print conditions (type of carrier, type of printing, colors printed, image capture conditions). It is observed that the density (i.e. the ratio of dark areas to light areas) of this test DAC and each definitive DAC (see below) can be dependent on the document and print conditions.
  • the printer prints a pilot set of documents bearing the test DAC.
  • the DAC provider determines threshold values to be utilized during the production run, i.e. the printing of the documents to be delivered, and at least one DAC, which represents, possibly, at least one adjustment parameter value to be applied when determining whether an image of a DAC represents an original DAC, i.e. printed during the production run, or a copy of an original DAC. In a variant it is an information matrix supplied by the DAC provider that represents each adjustment parameter value.
  • the DAC provider also determines threshold values to be applied during the production run.
  • the DAC provider supplies at least one definitive DAC and threshold values to be applied during the production run, and possibly adjustment parameter values, to the printer.
  • a step 830 an image of a printed DAC is captured.
  • a step 835 it is determined whether the image capture conditions are sufficient. If not, the method returns to step 830 . If yes, during a step 840 , the image's score is determined, the operator is supplied with a rating representative of this score and it is determined whether the DAC's image corresponds to a score value, possibly adjusted, that lies between the threshold values supplied during the step 825 . If yes, this score is stored during a step 845 , the production continues and the method returns to step 830 . Otherwise, an alarm is triggered during a step 850 and the documents being printed are rejected. Then the method returns to step 830 , document acceptance only being resumed when the alarm is lifted.
  • each adjustment parameter value (for example, additive or multiplicative) to be applied to the score of this production's DAC images according to the image capture quality, according to scores held in memory, and each adjustment parameter value is stored on the DAC provider's server.
  • Each parameter value represents the DACs' print quality and/or conditions.
  • a step 860 an image of a DAC is captured. Then, during a step 865 , the image capture conditions are determined. During a step 870 , it is determined whether the image capture conditions are sufficient, especially in terms of blurring, resolution and lighting, to allow the DAC to be interpreted. If not, the method returns to step 860 and/or the image is supplied to the DAC provider's server. If the image capture conditions are sufficient, during a step 875 , it is determined at least one adjustment parameter value (for example, additive or multiplicative) to be applied to the score of the DAC represented by the image, according to the image capture quality, in particular the blurring, the resolution and the uniformity of the lighting.
  • adjustment parameter value for example, additive or multiplicative
  • a step 875 it is determined at least one adjustment parameter value linked to the print and one threshold value to be applied, either by reading a part of the DAC's content, or by reading a content of an information matrix, or by requesting this value from the DAC provider's server.
  • step 885 it is determined, according to the various adjustment values and the threshold value, whether the image represents an original DAC or a copy.
  • the result from step 885 is transmitted to the DAC provider and, possibly, to the rights holder and, possibly, to the operator who performed the capture.
  • FIG. 7 The utilization of the various steps illustrated in FIG. 7 is detailed in other particular embodiments of the method that is the subject of this invention illustrated in FIGS. 1 to 3H .
  • FIG. 1 shows an embodiment of the identification device 100 that is the subject of this invention adapted to a document printing machine, or chain, in order to process these documents from their initial printing.
  • the document identification device 100 comprises:
  • the means 125 of reading the DAC 115 comprises a camera 126 and at least one light source 127 .
  • the reading means 125 also comprises a means of processing 129 the image captured by the camera 126 , which determines characteristics of the image of the DAC 115 .
  • the means 125 of reading the DAC commands a means of withdrawing (not shown) each document 100 bearing a poor quality DAC.
  • the means of withdrawing each document 100 bearing a poor quality DAC is, for example, constituted of a “reject gate”, i.e. a shutter controlled so that, in one of its positions, the documents fall into a waste bin and, in another position, the documents are let through to the stacker 107 .
  • the result of the verification carried out by the means 125 is transmitted, to be stored and used later, to a server 155 .
  • This server 155 supplies digital authentication codes and has the following functionalities:
  • a mobile means of reading DACs 190 is also shown in FIG. 1 .
  • the fixed reading means 125 and the mobile reading means 190 each comprise a means of communicating remotely with the server 155 , for example, by means of a telephony network, fixed or mobile, or the Internet network.
  • the integration of DACs for securing documents involves three parties: the rights holder wishing to produce secure documents, the provider of the service making documents secure via DAC, and the processor or the printer producing the documents secured by DAC.
  • a party can have two roles to play, for example the rights holder is also the provider of the securization service, or this latter is also responsible for printing documents.
  • the separation into three parties is relevant from a functional point of view since these are generally different departments that order, supply and print the DACs.
  • the access to the DAC images to be printed must be limited to trustworthy people.
  • the system must keep a complete audit trail in case of litigation.
  • the complexity of the human operations, which are sources of errors, is minimized, the procedures are automated and logs are kept of the operations carried out.
  • At least one printed DAC image is captured.
  • this process is done automatically, the products passing under the lens of the fixed reading means 125 .
  • This fixed reading means 125 is activated automatically or by an external activation from a capture device.
  • the mobile reader 190 is utilized by an operator to capture images of the DACs during production.
  • Each captured image of a DAC is stored in a database, with the associated information (manufacturing order, date, etc.).
  • a signature allows one print of a DAC to be identified uniquely among the prints of the DACs coming from a single source image (of the same DAC).
  • the site where the images of DACs are captured can be located at the printer's, with the advantage that it can be integrated into the production, and the disadvantage that it is in an exposed area.
  • the equipment used to calculate and/or store signatures can be secured, for example located remotely on the server and processing images supplied by one of the reading means 125 or 190 .
  • the site can be located at the third-party authorized by the rights holder, generally the same party that provides the DAC or DACs used.
  • the reliability of the copy detection depends on the stability of the score: from a statistical point of view, it is seek primarily to have the score with the smallest variance. That means that, from the beginning to the end of the production of products bearing a given DAC, the print conditions affecting the DACs' score must not change significantly.
  • this score is sensitive to a large number of parameters, for example the type of paper, the type of ink, and parameters generally adjustable on the print equipment, such as the ink density.
  • Print equipment is often very sensitive, and experience shows that for the same product printed on the same machine, the print parameters can change for print series carried out at different times, with a significant impact on the DACs' score.
  • the print parameters can change during a single production session, and a progressive shift of the score can thus be observed. Even a change of operator during the production session can have an impact on the print quality and therefore on the DACs' score. It is therefore seek to minimize these effects, in particular by providing for adjustments to scores.
  • the marking conditions are checked during the production, in order to ensure the essential DAC copy detection function. Equally, it is not uncommon for the printer, or the person in charge of integrating DACs in the files, to make an association error, such that a wrong DAC value comes to be assigned to a document to be printed.
  • the reading means 125 is absent, an operator is equipped with a mobile DAC reader 190 , in order to make regular checks of the production on the print chain.
  • the reader can be very similar to a regular DAC reader. However, it is preferable that it has the following characteristics: for preference it is easy to handle, for example taking the form of a stand-alone reader, or by a wire-type connection with a sufficiently long wire. Its main function is to check the production quality, therefore a binary response is, in general, not very suitable; the readers being located in distant areas, i.e. at the printers or sub-contractors, it is better to store a minimum of sensitive information locally (read algorithms, reading parameters) in the reading means 125 and 190 .
  • the operator receives a file of sets of DAC reading parameters (these parameters can be transmitted automatically via the printer's internal network) and is equipped with a mobile reader 190 , with a wire-type connection or not.
  • the set of parameters does not comprise the read keys, since there may be a security risk in distributing such a set of parameters. Therefore a sub-set of the DAC's values is stored, randomly sampled and of sufficient size to make it possible to measure a representative score for the quality check, but not large enough to recreate a DAC that is close to original DAC prints. If a DAC comprises, for example, 12,000 values, 2 , 000 of these values are stored in the file, chosen from positions that are random but known to the reader.
  • the operator reads the printing plate that bears it (for example, the one corresponding to the black ink), to make sure that the DAC has the right value and is of good quality. If this is not the case, he/she will have to produce a new plate, possibly with new DACs. Otherwise, he/she can start printing products in the preliminary print parameter adjustment phase. During this preliminary phase, the operator performs several checks of the DACs.
  • the procedure for securing documents first of all comprises, carried out by a server that supplies digital authentication codes:
  • the original image is sent to the server before step 230 and in the course of this step the server produces the DAC and sends it to the processing or print site.
  • the digital authentication codes sent in the course of step 230 are test digital authentication codes for integrating in the product's design.
  • a step of 235 printing a first pre-defined number of documents bearing a said digital authentication code is carried out, on the processing or print chain.
  • an image is captured of at least one, and preferably each, digital authentication code printed and an item of information representative of each printed digital authentication code is stored.
  • This image capture can be carried out manually or automatically, by an image capture device placed on the chain in question.
  • captured images of the digital authentication codes printed are sent to the server, from the processing or print site, as well as print parameter values utilized for printing the pre-defined first number of products.
  • the server determines an error rate in the digital authentication codes represented by the images, then a score and a print quality for the pre-defined first number of products, with a possible adjustment according to print conditions and image capture conditions. Then, during a step 255 , the server determines whether the production is valid based on measurements received, according to a pre-defined limit value, as described with reference to FIGS. 3A to 3D .
  • the server If the production is not valid, during a step 260 , the server notifies the user or the print chain of this, with indications of the modifications to be carried out on the print parameters (for example to reduce or increase the inking). Then, the method returns to step 235 .
  • a score or error rate limit value, or threshold value, for the DACs' authenticity validation is determined by the server from rates determined during step 250 .
  • This value is represented, in a secure way, by the DAC transmitted during step 265 .
  • this limit value corresponds to the authenticity validation of 98% of DACs printed during the last step 235 .
  • This value, together with an error margin, is transmitted to the reader on the chain and/or the manual reader.
  • this DAC is also representative of print parameters utilized during the last step 235 .
  • the error rate, score and print quality are determined locally by the reader carrying out image captures and they are transmitted to the server 155 .
  • a pre-defined second number of products, specified in the manufacturing order, is printed or processed utilizing the print parameters of the last step 235 .
  • an image of the printed DAC is captured, automatically or manually, on the print chain.
  • a rate of errors in the digital authentication codes represented by the images is determined, then a score and a print quality for the pre-defined first number of products, with a possible adjustment according to the print conditions and image capture conditions, according to a pre-defined limit value, as described with reference to FIGS. 3A to 3D .
  • the local reader determines whether the immediate production is valid according to the error margin, assigns a rating to the last image captured and supplies this rating to the print chain operator, by display.
  • the production is not valid, i.e. if the error rate is greater than the authenticity limit value added to the error margin, an alarm is triggered in order for the operator to re-establish the print parameters. Possibly, the products for which the production is not valid are eliminated and deducted from the number of products printed.
  • one or more signatures are calculated for each valid captured DAC image.
  • a signature generally the one occupying the smallest volume of data, is quantified and/or compressed so as to obtain a compact representation of it.
  • the set of calculated signatures is sent, by secure link, to the server which the inspectors connect to in order to verify the validity of signatures.
  • an information matrix preferably made secure with the help of an encryption key, is generated to contain the representation of the signature and printed on the document containing the DAC, during step 285 .
  • a validity limit value, or threshold value, of the DAC is determined during production, from measurements made during step 280 , and represented, in a secure way, by an information matrix printed during a step 295 .
  • the set of parameters received by the operator contains an average target score for the DAC, together with error margins.
  • the target score can be 15 and the error margin +/ ⁇ 2.
  • any score between 13 and 17 is accepted, but the wished-for score must be as close as possible to 15.
  • This score is not generally presented to the operator, but a transformation of this score, called the rating, is presented to him/her, in the course of step 280 , during production. This rating is easier for him/her to interpret, and can be compared between different production runs that might have different target scores.
  • One possible transformation consists of transforming the score on a scale of ⁇ 5 to +5, as follows:
  • a score of 14.2 gives a rating of +1, and a score of 16 a rating of ⁇ 1.25.
  • the rating can be quantified to the closest whole number.
  • the operator is asked for a minimum of readings, for example 30, taken in a uniform way during production, so as to determine the production's score statistics.
  • the printer or processor wishes to close the production session, the quality measurements carried out during the production session are sent to the server, and a decision concerning the production's validity is sent in return.
  • the production is deemed valid if:
  • a score that is greater than the target score is in reality more acceptable than a score that is lower than the target score.
  • a dissymmetry which can therefore be integrated by assigning a greater error margin in the first case.
  • the ratings displayed to the operator are transformed into ratings on a letter-grade scale, for example A, B, C, D, E with a + or ⁇ sign depending on whether the score is below or above the target score.
  • the rating is quantified beforehand.
  • +5 corresponds to E+, +4 to D+, +3 to C+, +2 to B+, +1 to A+, 0 to A, ⁇ 1 to A ⁇ , ⁇ 2 to B ⁇ , ⁇ 3 to C ⁇ , ⁇ 4 to D ⁇ , and ⁇ 5 to E ⁇ .
  • the position of the +/ ⁇ sign and the letter can potentially be inverted, since the sign is more significant.
  • target score and the error margin or margins are generally pre-calculated during a calibration phase for the printing machine and/or the ink and paper used and/or the target product, each able to have an impact on the DAC's score.
  • the adjustment phase can serve as a learning phase: a certain variation in the value of the target score can be tolerated, on condition that the whole production is as close as possible to this target score.
  • the priority is to minimize the variability of the score, and provided the variability is low, it is acceptable for the production's average score to differ from the target score.
  • a message can be sent to the operator depending on the rating, for example recommending increasing or reducing the level of inking.
  • the printing machine is directly controlled so that the rating remains as close as possible to the value “0”.
  • the scores, or error rates, are therefore presented to the operator and counted in the production statistics.
  • FIG. 3A shows, the following is carried out in order to check the quality of the authentication codes:
  • FIG. 3B shows, in order to check the quality of the authentication codes, in particular embodiments, the same steps as those shown in FIG. 3A are performed, except that steps 340 and 345 are eliminated and during step 425 , which follows step 320 , the error rate in the DAC's image is determined, then a score and, during a step 430 , the product's authenticity is determined, as described with reference to steps 340 and 345 but without adjustment according to the image capture conditions. If it is determined that the product is authentic, step 350 is proceeded to. Otherwise, steps 325 and 330 are carried out and, if the image capture conditions are sufficient, step 350 is proceeded to.
  • This embodiment applies, for example, to images produced by flat-bed scanners.
  • an image can be generated by different flat-bed scanners, which are not necessarily approved or even known.
  • These scanners produce images of variable quality: in effect there are a multitude of brands and models of flat-bed scanner, and moreover most of these scanners contain internal settings that can affect the quality of the captured image.
  • Knowing the scanner model does not generally mean the image quality is determined: in effect, for a given scanner the capture resolution (600 dpi, 1,200 dpi, 2,400 dpi) affects the image quality, and this is different on different models of scanners.
  • the type of image also affects the image quality.
  • the “smoothing” option of certain scanners corresponds to the application of a low-pass filter that can eliminate many details of the DAC, the score of which can therefore be reduced significantly. And other options can have a contrary effect on the score.
  • options such as “Sharpness enhancement” correspond to a high-pass filter, which can sometimes increase or reduce the DAC's score.
  • a specific application is installed on the work station connected to the scanner, in theory it may be possible to “freeze” the different capture parameters in order to check the image quality.
  • the scanner parameter management programs are proprietary programs, and do not give access to a majority of the internal parameters other than by a user interface, which can therefore be changed at any time without control.
  • the document to be verified can simply be poorly placed on the surface of the scanner, in such a way that the DAC's image is not taken at the scanner's focal point: its score can therefore be significantly affected by this.
  • the image capture tool can be of an unknown origin.
  • an image can be taken on any scanner whatsoever, then sent to a server for verification.
  • the name of the scanner is not transmitted to the server, and even if it was transmitted its image capture properties may be unknown, given the large number of models on the market.
  • test chart is an object, for example a card, that contains image structures allowing the quality of the image produced by the image capture device to be evaluated in an accurate and stable way.
  • the operator who has a test chart and wishes to authenticate a document places the test chart and the document alongside each other in the image capture device's field of vision, in such a way that a single image capture contains both the DAC or DACs to be analyzed and the test chart, during a step 605 .
  • An image of the test chart allows one or more indicators of the image quality to be calculated. These indicators are matched with reference values for the test chart, so as to adjust the DAC's score by taking into account the measurement of the image quality, during a step 610 and 615 and/or to determine whether the image is of a sufficiently high quality to determine the DAC's authenticity.
  • the test chart can also be a sticker that is stuck on the document to be verified, alongside the DAC. In this way, if the DAC is poorly positioned on the scanner so that it is blurred in the image generated, there is a strong chance that the test chart will also be blurred. It will therefore be possible to determine that the image does not allow the DAC to be authenticated.
  • the test chart itself contains a DAC.
  • the adjusted score is compared against each pre-defined threshold value for the DAC so as to make a decision concerning its authenticity, its signature, its rating and the identity of the product, as described with reference to FIG. 3A or 3 B.
  • Image quality problems can exist even with reading tools with properties that are, in theory, known.
  • a pool of readers is distributed to the sub-contractors, assembly units, quality department of the various rights holders and also to inspectors, customs officers, distributers. These readers are moved and operated with variable precautions, and sometimes some readers are out of adjustment.
  • a reader may not be perfectly adjusted when it leaves the factory. And in general it cannot be guaranteed that all the readers have exactly the same reading performance levels, even if they are manufactured in an identical way.
  • the scores, or the decision threshold values are adjusted so as to take the tool's performance into account. For preference, means of detecting an adjustment problem on a reading tool are provided for.
  • test chart such as those described earlier
  • the test chart is contained in every image captured with the capture means.
  • reading the test chart allows the image quality to be measured. This image quality can be taken into account in order to adjust the score measured for the DAC, or to display a message warning the operator of the reading means that an adjustment of this reading means is needed.
  • a threshold value can be established beforehand, corresponding to the best reading quality that can be obtained over a range of reading means.
  • the range of reading means can correspond to all flat-bed scanners operating at 1,200 dpi.
  • the threshold value can be established by one of the methods described above.
  • the DAC is considered to be an original if the score is greater than the threshold value.
  • the response message generally consists of recommending a more detailed verification, with the help of an image capture means with known performances, or otherwise with an image capture means providing a superior image quality.
  • the card equipped with the test chart can have other advantageous functions.
  • the test chart can contain information, for example in a DAC or SIM, allowing its holder to be identified. Thus, it can be ensured that only authorized people can read or authenticate the DACs. It can also be determined the DACs read for a given test chart, or even allow a maximum number of reads for a given test chart. This is also true if the test chart is on a sticker, as this can be destructible if one tries to remove it.
  • the reading means also makes it possible to draw up a payment model for the DAC reading service customer based on the number of reads performed.
  • Copy detection methods can be applied so as to detect a possible copy of a reading card.
  • print sharpness values are obtained, that can, for example, be pre-calculated during the image checking step and stored by the server 155 .
  • the steps utilized comprise, as shown in FIG. 3G :
  • the degree of sharpness can, up to a certain tolerated value, be used to adjust the DAC's score.
  • the method has complete control over the print context, and can store the expected value or threshold value for sharpness (as well as the threshold score value) in the message carried by the DAC; the method can also store these values in a 2D bar code during printing by overprinting.
  • an algorithm presented in FIG. 3H enabling blurred images to be determined in real time can be used. If the image contains a DAC and is judged to be sharp, the DAC can be authenticated, otherwise the method continues. It is noted that it may be possible to tolerate a certain number of good but rejected images. In contrast a systematic rejection of valid images (for example a non-blurred copy) is not acceptable.
  • the threshold value of the sharpness score can be absolute or determined according to the print conditions if these are known. For example, depending on the sharpness measurement, scores with different values for DACs that are offset printed can be obtained, or ink-jet printed (typically less high in the latter case). It is noted that the sharpness measurement can also vary according to the properties of the image capture tool and the resolution at which it is used. If necessary, the sharpness measurements are converted to take these properties into account, and the parameters of the sharpness measurement algorithm can also be adapted (for example the size of the neighboring area in question, which typically is larger if the capture resolution is higher).
  • an image difference is measured between the image received and the previous image, and the image is rejected if the difference measurement is greater than a threshold value.
  • a large image difference can indicate that the product or document is in movement and that its position is not stabilized, which increases the chances of the image being blurred.
  • the measurement of a sharpness score in the test chart is integrated in the algorithm given above.
  • a scanner-based remote reading application can verify the image quality with the help of the test chart.
  • This application is advantageous because no software has to be installed at the user.
  • the application entails several operations (setting the scanner's parameters correctly, possibly selecting the image part to be scanned, saving the digital image, or “scan”, in a file, sending the file to the server by electronic mail).
  • many users may not necessarily be familiar with this type of operation, and as a result will not use the application.
  • an operation error can easily occur, resulting for example in an image file that does not contain a DAC, or an image that does not have the required quality.
  • Installing local application software means that reading can be substantially simplified.
  • this local application software does not contain the DAC reading algorithms, or the related keys. In this way, the related security problems are avoided. Secondly, the problems of updating keys or parameters in the installed application software are avoided.
  • the local application software manages the scanner's parameters, determines the areas to be scanned, sends the DAC images to the server, and displays the server's responses on return. It can also detect problems, for example blurred images, before the image is sent to the server and indicate to the user how to correct these problems.
  • the DAC or DACs are read. For each DAC a sharpness measurement can be taken and compared to a threshold value stored on the server (this value can be retrieved if the DAC is identified). If the DAC's score is less than the threshold value corresponding to it and the sharpness measurement is also less than the threshold value corresponding to it, a message can, for example, be sent to the operator of the scanner, rights holder and/or DAC provider, indicating that it was not possible to authenticate the image.
  • FIG. 3C shows the steps utilized in this particular embodiment.
  • the error rate (or quality) and sharpness scores can vary according to the image capture conditions: quality, resolution, lighting, etc.
  • the measurements made during calibration (see FIGS. 2A and 2B ), during the quality check in production or during delivery of products to the processor or any other recipient designated by the rights holder, which serve as a reference for the expected measurements, must be adapted to the image capture conditions if they have been carried out with an image capture tool producing different types of images.
  • a printed DAC (or several prints of the same DAC), serving as a reference, is chosen.
  • this DAC is correctly printed with no particularity, for example its level of inking is not too high.
  • image captures are carried out with the reference image capture tool, for example the one that serves in the quality check in production or when documents are received.
  • An average, “m”, and a standard deviation, “e”, are calculated for the score, for example, by using robust statistical methods.
  • n is a positive value that depends on the maximum probability of the false detection of a copy that is acceptable.
  • the image capture tool is different from the image capture tool used when calculating the statistical distribution of the scores.
  • the image capture tool will be of poorer quality, such that the average “m′” of the scores for this tool is less than “m”.
  • a conversion function “f” of the scores between the two image capture tools is calculated: to do that, DACs are printed with different print qualities. Images of these are captured with the different image capture tools used, and the conversion function that has to be applied to the different levels of score obtained with these different image capture tools is determined.
  • the conversion function is considered to be an additive or multiplicative type, and the multiplier or additive coefficient to be applied is determined.
  • this solution cannot always be applied since, as previously discussed, the image capture tool used is not always known.
  • an image of a test chart has also been captured during the image-taking and, for preference, this test chart contains another DAC for which the score on a reference tool is known. It has been seen previously how this test chart can be used to determine whether the image quality is sufficient.
  • This test chart can also be used to adjust the score obtained for the DAC to be authenticated. For example, if the DAC serving as a test chart obtains a score of 12, while this score is 13 on average on the reference image capture tool, a multiplicative coefficient of 13/12 can be applied to the score of the DAC to be authenticated.
  • this new method makes it possible, within certain limits (a score below a pre-defined limit for the test chart's DAC leading to the captured image being rejected), to carry out a score adjustment that, although it may be approximate, nevertheless allows the risks of errors (in particular the risks of considering a original to be a copy on a poorer quality image capture tool) to be reduced.
  • the image quality can be estimated in various ways, for example by applying low-pass filtering, preferably Gaussian, to the image, and by measuring a difference, for each image pixel, between the filtered image and the original image, then by calculating an average for the image difference. An average can also be calculated by favoring the DAC areas with a greater contrast. In general, the image-taking quality will get less as this difference gets smaller. It is noted that other analog methods, for example based on measuring the power spectrum in frequency for the captured image, can be used as an indicator of sharpness.
  • low-pass filtering preferably Gaussian
  • the relationship between the sharpness indicator and the score correction factor must be predetermined. For example, one or more printed DACs with the same print quality are chosen, and their score and sharpness indicator are calculated on image capture tools that have different qualities. The relationship between the sharpness indicator and the score correction coefficient can then be estimated by statistical methods. The same procedure can be repeated for DACs with different levels of print quality, and therefore different levels of score, when the image is captured with a reference image capture tool. It is noted that, for the best results, it is preferable to take the possible differences in image capture resolutions into account in calculating the sharpness indicator and also the image's dynamic.
  • document is used to refer to any information carrier readable with reading equipment and, sometimes, by eye and “anti-copy mark” or “mark” is used to refer to a mark intended to be made, by printing or by local physical modification of the carrier, on a document and whose degradation, when this document is copied, is detectable and allows the original to be distinguished from the copy.
  • anti-copy mark or “mark” is used to refer to a mark intended to be made, by printing or by local physical modification of the carrier, on a document and whose degradation, when this document is copied, is detectable and allows the original to be distinguished from the copy.
  • FIG. 8 is not shown to scale, either.
  • FIG. 8 shows an item of printing equipment 1005 equipped with an item of copy detection equipment 1010 , a server 1015 providing anti-copy marks, a server 1020 holding a database of authorized degradation measurements, a server 1025 of an owner of rights on a document, warning means 1030 , for example a rotating light, a sound emitter or production control computer and an item of mobile copy detection equipment 1035 .
  • the printing equipment 1005 is of any type whatsoever, for example flexography, gravure, offset, typography, digital, laser or ink-jet printing.
  • the copy detection equipment 1010 and 1035 comprise a means of taking an image 1040 of a mark on a document, for example a charge transfer image capture device, known under the name “CCD” (acronym for “charge coupled device”), a processor 1045 and a non-volatile memory 1050 holding a software system implementing steps shown in FIGS. 9A and 9B .
  • CCD charge transfer image capture device
  • the copy detection equipment 1010 also comprises a means of remote communication 1055 with the server 1020 and/or the server 1015 , for example on a fixed or mobile telephony network.
  • the copy detection equipment 1035 also comprises a means of remote communication 1060 with the servers 1020 and 1025 , for example on a mobile telephony network.
  • the server 1015 providing anti-copy marks is designed to implement step 1165 shown in FIGS. 9A and 9B to provide an anti-copy mark according to the printing equipment characteristics.
  • the server 1020 holds a database of authorized degradation measurements matched with identifiers of printed documents. As will be seen below, the server 1020 is optional, an anti-copy mark being able, in embodiments, to incorporate the degradation limit measurement or measurements allowing an original document to be distinguished from a copy.
  • the server 1025 of an owner of rights on a document is designed to archive and process information from the mobile copy detection equipment 1035 to determine a document's route, especially in the case when a copy is detected.
  • a printer fills out a questionnaire describing, in particular, the type and brand of an item of printing equipment intended to be used for printing documents bearing an anti-copy mark, and all the graphics chain parameters, for example of the “CAP” (acronym for “computer-assisted publishing”) system of the “RIP” (acronym for “rastering image process”) system which is expressed in a “bitmap” file, i.e. representing each dot of the image separately for each color and the “CTP” (acronym for “computer to plate”) system or “FTP” (acronym for “film to plate”) system, which engraves the printing plate.
  • CAP acronym for “computer-assisted publishing”
  • RIP an “rastering image process”
  • the completed questionnaire is supplied by the printer to a provider of anti-copy marks.
  • the provider prepares and supplies a template of calibration files to the printer, according to the contents of the completed questionnaire, which represents the physical configuration of the printing machine. For example, from the width, the supplier determines where to place the template (for example a dimension of 105 ⁇ 210), given that this template is to be reproduced several times on test sheets. Preferably, it is set up for the template to allow each color printed (each print group) to be identified since an anti-copy mark is integrated for each print group. In other embodiments, an anti-copy mark is only provided for the color, for preference black, with which this mark will be printed.
  • the provider of marks determines a calibration mark, according to the contents of the completed questionnaire. Knowing the native resolution of the printing equipment, generally 2400 points per inch, the resolution of the anti-copy mark is chosen so that the original's print itself comprises a sufficient mark degradation, for example greater than a pre-defined value.
  • the provider supplies the file template and the calibration mark to the printer, preferably in an attachment to an electronic mail.
  • the printer completes a calibration file, i.e. during the design of a test sheet comprising several files intended to be printed in different places and in different colors, he/she adds a mark, for example a cross, in a box corresponding to the print color and position. Similarly, he/she identifies the equipment used for printing.
  • the printer associates an anti-copy mark supplied during step 1125 to each file realized based on the template.
  • the printer prints the calibration mark with the printing equipment, preferably in different central and side print areas of the printing equipment and preferably for the most common reference cardboard in production.
  • the printer prints the mark on different types of paper or cardboard, in different paper weights.
  • the printer supplies the completed calibration file and the mark or marks printed by the printing equipment to the provider of marks.
  • the provider measures the degradation of at least one anti-copy mark printed with the printing equipment with a view to statistical processing to determine a standard deviation between the file prints.
  • the provider of marks determines the characteristics of an item of printing equipment, according to the degradation of at least one mark printed with the printing equipment to be used and supplies a mark having these characteristics to the printer, who integrates them in the matrix of the document to be printed, for example the offset films. For example, the provider determines, statistically, a standard deviation for the number of print errors of the anti-copy mark printed during step 1135 . Depending on this standard deviation, the utilization capacity of the printing equipment and its context are verified. Possibly, during step 1150 , the provider adjusts the print resolution of the anti-copy marks.
  • a galley proof is a physical print sample of the document, accepted by the principal in terms of the processing quality. It is signed by the customer and serves as a reference standard or setting standard for the printing equipment at the start of each production run. This is a very widespread work tool and is systematically used in the print world.
  • the galley proof corresponds to three print situations:
  • an item of copy detection equipment is utilized to measure, on at least one of the extreme panels of the galley proof corresponding to an extreme inking load, the degradation of the anti-copy mark.
  • the standard inking represented by the galley proof's central panel, defines, by means of the copy detection equipment, a standard error rate, or degradation measurement.
  • the measurement is performed at least on the galley proof panel presenting the minimum inking load authorized by the customer.
  • each panel is the subject of a degradation measurement and the highest degradation measurement is selected. It is recalled that a degradation measurement can determine the number of the mark's dots that do not have the digital original's color. This measurement can be carried out by comparing an image of the analyzed mark with a digital image without degradation, for example.
  • an item of information representative of the degradation measurement obtained during step 1155 is stored in the memory of an item of copy detection equipment installed on the item of printing equipment.
  • This item of information is, for example, the error rate measurement for each extreme inking load authorized.
  • a safety margin for example a multiple of the standard deviation, is added to the degradation measurement obtained during step 1155 for the standard inking and the result is stored.
  • two limit values are determined, by adding or deducting the safety margin of the error rate obtained with the standard inking load.
  • the storage is done in a remote database (see server 1020 shown in FIG. 8 ), by storing the limit value or values in association with an identifier of the document in the database.
  • the storage is done in a new anti-copy mark supplied by the provider of anti-copy marks for the production of original documents.
  • the anti-copy mark therefore has an encoding or an encryption of the limit value or values.
  • the anti-copy mark integrates, in a known way, an item of information representative of the limit value or values.
  • a step 1170 the document is produced, generally in mass production.
  • the degradation of the anti-copy marks is measured, with the copy detection equipment installed on the printing equipment.
  • the document is identified, either from information contained in the anti-copy mark or in a data carrier associated to this mark, for example a bar code, possibly two-dimensional, for example a datamatrix (registered trademark), or by inputting the visible information that is attached to it (model and manufacturer, for example).
  • a data carrier associated to this mark for example a bar code, possibly two-dimensional, for example a datamatrix (registered trademark), or by inputting the visible information that is attached to it (model and manufacturer, for example).
  • steps 1195 and 1200 can form just one step, in particular when an identifier of the document is read by processing an image of the anti-copy mark.
  • a step 1205 it is determined whether the measurement made during step 1200 is greater than the measurement stored during step 1190 . If it is, during a step 1210 information concerning the mark analyzed or the product in question is transmitted remotely, so that the rights owner can act against potential counterfeiting of his/her product associated to the document. For example, this communication is carried out utilizing a mobile telephony network. Otherwise, at regular intervals of time, for example once a day, during a step 1215 information concerning the documents analyzed is transmitted remotely, so that the rights owner can trace his/her products.
  • step 1210 the method returns to step 1195 .
  • steps 1160 and 1190 can be eliminated in the case in which the anti-copy mark represents, in the information it incorporates, the limit value or values that, for step 1175 , represent the warning signal trigger threshold or thresholds and, for step 1205 , represent the threshold or thresholds for distinguishing an original document from a copy.
  • the two extreme situations represented by the galley proof define the maximum error rate, or degradation measurement, authorized for ascertaining that a document is an original, within a tolerance margin.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • General Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Editing Of Facsimile Originals (AREA)
  • Accessory Devices And Overall Control Thereof (AREA)
US12/519,256 2006-12-14 2007-12-14 Method and device against forgery Abandoned US20110038012A1 (en)

Applications Claiming Priority (9)

Application Number Priority Date Filing Date Title
FR0610891 2006-12-14
FR0610891A FR2910148B1 (fr) 2006-12-14 2006-12-14 Procede et dispositif de securisation de documents.
FR0611402A FR2910667B1 (fr) 2006-12-26 2006-12-26 Procedes d'identification et de traitement d'un document
FR0611402 2006-12-26
FR0703922A FR2916678B1 (fr) 2007-06-01 2007-06-01 Procede et dispositif de securisation de documents
FR0703922 2007-06-01
FR0704517 2007-06-22
FR0704517A FR2917877B1 (fr) 2007-06-22 2007-06-22 Procede et dispositif de marquage d'un recipient et procede et dispositif de lecture d'information sur un recipient marque
PCT/FR2007/002085 WO2008107525A2 (fr) 2006-12-14 2007-12-14 Procede et dispositif de lutte contre la contrefaçon

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WO2016163887A1 (fr) * 2015-04-09 2016-10-13 Filigrade B.V. Procédé de vérification d'authenticité d'un article imprimé et terminal de traitement de données
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US20090161957A1 (en) * 2007-12-20 2009-06-25 Canon Kabushiki Kaisha Constellation detection
US8244067B2 (en) 2007-12-20 2012-08-14 Canon Kabushiki Kaisha Constellation detection
US20130287307A1 (en) * 2010-07-28 2013-10-31 Microsoft Corporation Data difference guided image capturing
US9183465B2 (en) * 2010-07-28 2015-11-10 Microsoft Technology Licensing, Llc Data difference guided image capturing
NL2006990C2 (en) * 2011-06-01 2012-12-04 Nl Bank Nv Method and device for classifying security documents such as banknotes.
WO2012165959A1 (fr) * 2011-06-01 2012-12-06 De Nederlandsche Bank N.V. Procédé et dispositif de classification de documents de sécurité, tels que des billets de banque
US20130215473A1 (en) * 2012-02-16 2013-08-22 Xerox Corporation System and method for creating machine-readable codes in combination with other images such as logos
US8830533B2 (en) * 2012-02-16 2014-09-09 Xerox Corporation System and method for creating machine-readable codes in combination with other images such as logos
US20140201094A1 (en) * 2013-01-16 2014-07-17 Amazon Technologies, Inc. Unauthorized product detection techniques
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US20160373605A1 (en) * 2014-03-03 2016-12-22 Advanced Track & Trace Method of rendering a document secure
US10404886B2 (en) * 2014-03-03 2019-09-03 Advanced Track & Trace Method of rendering a document secure
US10699507B2 (en) 2015-04-09 2020-06-30 Filigrade B.V. Method of verifying an authenticity of a printed item and data processing terminal
WO2016163887A1 (fr) * 2015-04-09 2016-10-13 Filigrade B.V. Procédé de vérification d'authenticité d'un article imprimé et terminal de traitement de données
US11315378B2 (en) 2015-04-09 2022-04-26 Filigrade B.V. Method of verifying an authenticity of a printed item and data processing terminal
US20160316097A1 (en) * 2015-04-22 2016-10-27 Email Data Source, Inc. Method and system for generating a privatized electronic image for a plurality of electronic documents
US10104265B2 (en) * 2015-04-22 2018-10-16 Email Data Source, Inc. Method and device for generating a privatized electronic image for a plurality of electronic documents
US20160371531A1 (en) * 2015-06-16 2016-12-22 Morpho Biometric identification method
US9922234B2 (en) * 2015-06-16 2018-03-20 Morpho Biometric identification method
US20170006181A1 (en) * 2015-07-03 2017-01-05 Konica Minolta, Inc. Printed material processing device and non-transitory recording medium storing computer readable program
US10079958B2 (en) * 2015-07-03 2018-09-18 Konica Minolta, Inc. Printed material processing device and non-transitory recording medium storing computer readable program
US20170177961A1 (en) * 2015-12-22 2017-06-22 Safran Identity & Security Biometric identification method and device using one
US10489667B2 (en) * 2015-12-22 2019-11-26 Idemia Identity & Security Biometric identification method and device using one
US11651093B1 (en) * 2022-02-24 2023-05-16 LendingClub Bank, National Association Automated fraudulent document detection

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